Help to decide please!

Hi,
just want a suggestion on the job i am about to do,
basically i am selling digital mockups for apparel, and have a client wanting to have done mockups for sweatshirts just for his shop, so i can not sell it to anyone else, i am in doubt on:

  1. Price
  2. should i even agree to that??
    bc a lot of my graphics inventory that i will style his apparell, i wont be able to use to public, and it is a lot of work, 42 colors of the 2 types of sweaters and all individually styled.

HELP!
Thanks
Vika